1. Field of the Invention
The present invention relates to an electrical apparatus, including an electrolytic condenser and electrical components using synthetic resin.
2. Description of the Related Art
Various electrical apparatuses are reduced in size and weight to be compact. Such electrical apparatuses, for example discharge lamp lighting apparatuses, are provided with a housing and a circuit board having electrical components mounted on a printed circuit substrate. Typically, a discharge lamp lighting apparatus, using an inverter circuit, is miniaturized, as the size of the inverter circuit is smaller than that of a ballast, using a core and coil as a current-limiting reactor.
Japanese Laid Open Patent Application HEI 8-329731 (prior art) discloses an electrical apparatus using electrical components. According to the prior art, a circuit board is accommodated by a housing to insulate the circuit board electrically. Temperature of the housing tends to increase and may be over 70 degrees centigrade. In this case, electrical components are distinguished between heat generating parts and less heat generating parts. Each of the distinguished components is mounted on a predetermined heat area or less heat area of the circuit board. A shelter is constructed and arranged between the predetermined heat area and the less heat area in order to block off heat, generated at the predetermined heat area, from the less heat area. Therefore, electrical components can be protected from the heat.
However, as the electrical apparatuses become more compact in size, the temperature therein tends to rise. Therefore, electrical components cannot sufficiently be protected from the heat, even if the shelter is used in the electrical apparatuses. Accordingly, it is desired to use heatproof electrical components. A synthetic resin, used in the heatproof electrical components, contains one or more flame retardant halogen compounds, resistant to burning or giving off smoke, when the temperature of the housing of the electrical apparatuses rises excessively.
However, when heatproof electrical components were used, it sometimes happened that an electrolytic condenser of the electrical components did not operate due to insufficient charge.
The electrolytic condenser is generally provided with a body filled with electrolytic solution, a pair of lead wires, and a packing rubber. According to the circumstances, the electrolytic condenser sometimes leaked out the electrolytic solution and failed. When inventors analyzed the electrolytic condenser, they found out that the leaking of the electrolytic solution was caused by corrosion of its electrodes or terminals made of aluminum. Furthermore, the inventors analyzed the leaked electrolytic solution, in order to find what caused the corrosion of the electrodes. As a result of the analysis, the leaked electrolytic solution was found to include bromine (Br) at a concentration of 3 PPM.
After the bromine penetrated the electrolytic solution through the packing rubber, it is considered that the bromine (Br) ionized and made the electrodes corrode as follows:
2Al+6HBrxe2x86x922AlBr3+3H2. 
Then, it is presumed that the inner pressure of the electrolytic condenser increased, as the corrosion of electrodes gradually progressed. After the inner pressure excessively increased, a safety valve of the electrolytic condenser operated and the electrolytic solution leaked out.
When the inventors also analyzed the packing rubber of the electrolytic condenser, they detected bromine in the packing rubber. The concentration of the bromine inside the packing rubber was less than the concentration outside the packing rubber. Therefore, the inventors concluded that the bromine migrated through the packing rubber from outside the electrolytic condenser, and entered into the electrolytic solution.
Furthermore, the inventors investigated the causes of generation of the bromine, and found out that some of the electrical components emitted the bromine. For example, a film condenser, which included epoxy resins, included a halogen compound (flame retardant) such as hexabromobenzene (C6Br6) resistant to burning or giving off smoke. As the temperature of the electrical apparatus increased during a long operation, the temperature of the film condenser also rose. Accordingly, hexabromobenzene gradually sublimed or decomposed, so that the sublimed hexabromobenzene gas moved to the electrolytic condenser. It was estimated that the sublimed hexabromobenzene gas penetrated the electrolytic condenser through the packing rubber.
According to one aspect of the invention, an electrical apparatus comprises a circuit board providing an electrolytic condenser and electrical components, and a housing. The housing accommodates the circuit board. The electrical components include resin containing one or more halogen compounds of about 1% by weight or less in terms of bromine (Br).
According to another aspect of the invention, an electrical apparatus comprises a circuit board providing an electrolytic condenser and electrical components, and a housing accommodating the circuit board. The electrical components include resin containing one or more halogen compounds. The electrolytic condenser is covered with a cover element.
According to another aspect of the invention, an electrical apparatus comprises a circuit board, providing an electrolytic condenser and electrical components. The electrical components include resin containing one or more halogen compounds. The electrolytic condenser is covered with a cover element. A housing defines an air hole near the electrolytic condenser, and accommodates the circuit board.
According to another aspect of the invention, an electrical apparatus comprises a circuit board, providing electrical components including resin containing halogen compound. One end of an electrolytic condenser is arranged on the circuit board facing away from the electrical components. A housing accommodates the circuit board.
According to another aspect of the invention, an electrical apparatus comprises a circuit board, electrical components, an electrolytic condenser, a heat sink, and a housing. The housing accommodates the circuit board. The electrical components include resin containing one or more halogen compounds. A heat sink is constructed and arranged between the electrolytic condenser and the electrical components.
According to another aspect of the invention, an electrical apparatus comprises a circuit board, providing an electrolytic condenser and electrical components. The electrolytic condenser includes a body filled with ethylene glycol type-electrolytic solution, electrodes arranged in the body, lead wires extending from the body, and a packing rubber made of butyl rubber. The electrical components include resin containing one or more polymer type-halogen compounds. A housing accommodates the circuit board.
According to another aspect of the invention, an electrical apparatus comprises a circuit board, providing an electrolytic condenser and electrical components. The electrolytic condenser includes a body filled with ethylene glycol type-electrolytic solution, electrodes arranged in the body, lead wires extending from the body, and a packing rubber made of butyl rubber. The electrical components use resin, which contains one or more monomer type-halogen compounds. A housing accommodates the circuit board.
These and other aspects of the invention are further described in the following drawings and detailed description of the invention.